Metallurgical furnace



H. B. BBYSON. METALLURGICAL FURNACE. APPLICATION man SEPT. 26, 1917.

1,358,703. Patented Nov. 16, 1920;

wrmzssss mvcu'ron in some respects.

UNITED STATES PATENT OFFICE.

HARRY IB. lBBY SON, OF PITTSBURGH, PENNSYLVANIA. I

METALLURGICAL FURNACE.

. Specification of Letters Patent.

Patented Nov. 16, 1920.

' Application filed September 26, i917a Serial No. 193 280.

ToaZZ whom it may concern:

Be it known that I. HARRY B. BRYSON, a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Metallurgical Furnaces, of which the fol-.

provide an improved process of and apparatus for reducing and refining metal-bearing substances.

More particularly, theobject is to improve the construction and operation of furnaces by means of which, in a furnace of the open-hearth type. conditions can be created which are similar to those that exist at the present time only in graphitic crucible or electric furnaces.

I, A further object is to provide a furnace of the open-hearth or regenerative type which is so constructed that it may be easily repaired or-relined, and charged and discharged expeditiously.

Other objects and advantages of the invention will appear fromthe following specification.

A suitable apparatus by means of which the process may be carried out is illustrated in the accompanying drawing, which shows a cross section of the improved apparatus.

The process will first be described generally, and then the apparatus explained, v after which the manner of carrying out the process, with the apparatus, will be set forth.

In the manufacture of steel the physical properties are governed very largely'by the carbon content. It is rather difficult to accurately control the carbon content unless the iron used in making the steel is in the form of pig iron of known analyses, and the entire process carried out carefully under predetermined conditions. If ore or scrap or other sources of iron are used, the carbon content is very uncertain, and the steel pro duced is not of uniform character. The crucible furnace and the electric furnace have been used for this purpose, but they are quite expensive and not entirely satisfactory.

The present process has been devised for producing steel of homogeheous structure and uniform carbon content, such as is now produced 1n one pot of a crucible furnace or in an electric furnace, and to effect this result by creating in a furnace, preferably .of theopen-hearth or regenerative type,

conditions similar to those existing in thecrucible and electrlc furnace processes of making*steel, thereby so altering and improving the working conditions in the openhearth furnace that it will be especially adapted to give the same or better results than are now obtained. in the crucible or electric furnaces. By means of this improved process and apparatus, steel of the highest grade can be produced at a much lower cost than with the use of the furnaces to which reference has been made. While the process and apparatus is particularly adapted for producing steel, it may be used for refining various other metals, and, generally stated, the process and apparatus may be employed for economically reducingand refining various metals, especially reducing iron from" its ore, from scrap, or from other iron-bearing substances,'and refining 'itto manufacture steel.

Conditions similar to those now existing in the crucible or electric furnace. are created in a furnace of the open hearth or simi-, lar type, by constructing the floor or bottom and portions of the sides ofthe furnace of graphitic bricks'or blocks soarranged as to form a graphitic cup or bowl into which the metal-bearing substances are charged, and having the molten metal-bearing substances in this cup or bowl covered with a vitreous slag, which acts as a lid or cover to the graphitic bowl and thus establishes improved conditions, similar to the crucible and electric furnace. conditions.

The furnace for carrying out this process is constructed, in a general way, similar to the present type of open-hear h furnaces, but the'fioor and: part of the sides are made of graphitic bricks which are built into the furnace in such a way as to form an integral or fixed part of the structure, the arprocess. The graphitic floor is also made mechanically detachable so that itvmay be renewed or replaced and another bottom or floor substituted. The entire furnace is constructed so that the interior is. readily accessible, and is also arranged so that it may be turned or tilted into a position to allow the molten metal to be readily poured out.

i The furnace comprises a lower body portion 1, and an upper or roof portion 2, the

- tilting the furnace to the necessary position for pouring the metal, through the pouring spout 9, and returning the furnace to normal position. This construction permits the entire furnace to be easily manipulated for the purpose of discharging the reduced metal.

The bottom, sides and ends of the interior of-the base portion 1, of the furnace, are lined with ,carbon or graphitic blocks or bricks 10, as illustrated. These bricks are of good size and in addition to the carbon, contain asuitable amount of silica, or. clay free from iron, or both, making them fairly hard; and preferably are positioned in the bottom of the furnace so as to form an in -verted arch, thus preventing the bottom of the furnace from lifting during the heat. By building the lining in this manner, a graphitic cup or bowl is formed in which the metal maybe: reduced without destroying the lining during the process of reduction. The lining forms, in effect, an integral part of the furnace, but may nevertheless be removed after the furnace has been used for some time and replaced by a new lining.

This construction of furnace partly con- Verts the open-hearth furnace into a crucible and causes the lower portion of thefurnace to perform both the functions of the crucible and of the carbon electrodes of the electric furnace, namely; it actsas a container forfthe molten metal and maintains the molten metal in a' state of fluidity, when in the final state of reduction, it is, in a carbonless state, precipitated from the bath; and is also re-carbonizes the precipitated molten metal to a desired degree; with an added advantage over the electric furnace that the heat applied to the charge is applied evenly to all parts of the charge, whereas in the electric furnaceit is applied unevenly or locally by the electrodes. It is to be understood that the heat is applied in the present furnace to all parts of the furnace, as in the usual open-hearth I furnace of the regenerative or open type,

and preferably by the use of powdered coal as fuel. M

In practising the process with this improved constructionof furnace, the metalbearing substances are placed in the graphitic cup or bowl, and, together with such limestone, silica or other'flux as the nature of the charge may require, with each charge there is added' a suitable amount of readily fusible earthy matter, such as kaolin, baux- 1 ite, feldspar, or any compound of aluminum, magneslum sodlum or potasslum, to form a vitreous slag. Heat is then applied in the usual manner and-"the vitreous slag forms in the first stages (if the reduction process, and, being of a jlower specific gravity than the metal-bearing elements-in the bath, it rises to the surface of the bath and, automatically forms a lid or covering for the graphitic crucible, thereby creating crucible and electric furnace conditions.

This lid, or vitreous covering, serves two .acter, it takes up and retains most of the impurities of the metal-bearing elements of purposes: first, owing to its chemical charnace and the process employed, a -furnace of the open-hearth type is constructed and k utilized in such a way that it possesses all the advantages of the crucible and the electricfurnaces, and may be used for producing steel directly from ores, iron scrap, or

other iron-bearing substances. No pig iron need be used. When making steel of high grade or fine quality, ore or scrap of a definitely fine character will be selected.

It is to be understood that variations may be made in the exact construction of the furnace, and that the process may be' used, with or without slight modifications, for reducing other metal-bearing substances. The drawings are merely illustrative and variations may be made therein and in the process, all of which are included within the invention as defined by the appended claims.

What is claimed is 1. The process of making steel directly from iron ore, scrap, or the like, which consists in heating the iron-bearing substances in a carbon-lined furnace, andmaintainin the molten metal in said receptacle covered and sealed by a vitreous slag, thereb maintaining crucible conditions in said urnace.

2. The process of making steel directly from iron ore, scrap, or the like, which conand sealed by a vitreous slag of earthy ma terial, thereby maintaining crucible conditions in said furnace.

3. The process of making steel directly from iron ore, scrap, or the like, which consists in heating the iron-bearing substances in a carbon-lined furnace, and maintaining the molten metal 1n sald furnace covered and sealed by a vitreous slag of baux1te, or

- the like, thereby maintaining crucible conditions in said furnace.

4:. The process of making steel directly from iron ore, scrap, or the like, which consists in heating the iron-bearing substances from iron ore, scrap, or the like, which cons1sts m'heatmg the iron-bearing substances '25 in an open hearth type furnace provided with a carbon lining, andmaintaining the molten metal in said furnace covered and sealed by a vitreous-slag of earthy material,

thereby maintaining crucible conditions in said furnace.

6. The process of making steel directly from iron ore, scrap, or the like, which conslsts in heating the iron-bearing substances in an open hearth type furnace provided with a carbon lining, and maintaining the molten metal in said furnace covered and sealed by a vitreous slag of bauxite, or the like, thereby maintaining crucible conditions' in said furnace.

In testimony whereof I have hereunto set my hand.

HARRY B. BRY-SON. Witness:

GLENN H. LEREBQHE. 

